Currently, there is no clear diagnostic test that can be used to confirm the diagnosis of Parkinson's disease, or a biomarker that can track its progression. Patients with Parkinson's have many abnormalities of the autonomic nervous system, which may be related to Parkinson's changes outside of the brain. A new device called the SudoScan, which measures autonomic sweating changes, may be a simple way to test for autonomic changes in Parkinson's.